Fix compute service set command

add ``Binary name`` to help msg of compute service set command.

Change-Id: I5ed3824ec5bede250ce41f187835e8901b5e11fd

Author: sunyajing

doc/source/command-objects/compute-service.rst

@@ -80,5 +80,5 @@ Set service command
 
 .. describe:: <service>
 
-    Name of service
+    Name of service (Binary name)
 

openstackclient/compute/v2/service.py

@@ -105,7 +105,7 @@ def get_parser(self, prog_name):
         parser.add_argument(
             "service",
             metavar="<service>",
-            help=_("Name of service")
+            help=_("Name of service (Binary name)")
         )
         enabled_group = parser.add_mutually_exclusive_group()
         enabled_group.add_argument(